JP2022058167A - Reticle pod with antistatic performance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reticle pod having antistatic performance so as to accept a reticle carrying an electrostatic charge in consideration of a reticle defect caused by an electrostatic charge in an EUV process.
A reticle pod with antistatic performance has a base (212) and a support member (2121). The base has a support surface (2122) formed by a recess (2124) and a bottom surface. The support member is adapted to support the reticle while surrounding the supporting surface of the base. The recess is defined by the depth extending between the supporting surface and the bottom surface. Depths range from 300 μm to 3400 μm, thereby reducing the electrostatic force exerted on the particles on the supporting surface.
[Selection diagram] FIG. 5

Description

The present disclosure (the present invention) relates to a reticle pod, particularly a reticle pod having antistatic performance.

The reticle used in the conventional EUV process must be protected by a dedicated EUV reticle pod. FIG. 1 shows a reticle pod that receives an EUV reticle, which has an outer pod (100) and an inner pod (110) and is defined by an outer pod (100) and an inner pod (110). It has a layer and an outer layer receiving space. The outer pod (100) has a lid (101) and a base (102), and the lid (101) and the base (102) are coupled to each other to define a receiving space for receiving the inner pod (110). The inner pod (110) has a lid (111) and a base (112), the lid (111) and the base (112) receiving the reticle (120) and providing an airtight seal to the reticle. They are joined together by dedicated means to demarcate the space.

When the reticle (120) is received in the inner pod (110), the edge or bottom of the reticle (120) is supported by a support member (1121) provided on the base (112), resulting in the reticle (120). ) Downward facing surface is slightly higher than the upward supporting surface (1122) of the reticle (120). The upwardly facing support surface (1122), which is simply referred to as the "support surface (1122)", is surrounded by the support member (1121), and the support surface (1122) is a pattern zone (120) of the reticle (120). The area is wider than the area (not shown). The carrier surface (1122) is different from the upward facing contact surface (1123) that is provided around the base (112) and is in contact with the lid (111). The upwardly facing contact surface (1123) is in the shape of a ring.

The reticle (120) taken out from the exposure apparatus exhibits a residual voltage, which is more than 50V. When the reticle (120) with residual voltage is returned to the inner pod (110), particles adhering to the base (112) may be adsorbed to the bottom of the reticle (120). If the particles are adsorbed on the pattern zone of the reticle (120), the reticle (120) will cause pattern defects in the next stage of the exposure process.

FIG. 2 shows the steps of approaching the charged reticle (120) to the base (112). Although the base (112) is grounded and thus does not charge it, the particles (P) are present on the top surface (eg, the above-mentioned carrier surface (1122) of the base (112)). When the charged or charged reticle (120) approaches the base (112) to some extent, the electric field generated by the negative charge of the reticle (120) causes the top surface of the base (112) and the particles (P) to generate a positive charge. When the reticle (120) is fairly close to the base (112), the strength of the electrostatic field is sufficient to attract the particles (P) so that the particles (P) escape from the top surface of the base (112). Thus, it becomes adsorbed to the bottom of the reticle (120). Obviously, grounding the base (112) cannot solve all the defects caused by static charges.

Considering the reticle defects caused by static charges, it is necessary to provide a reticle pod with antistatic performance to accept statically charged reticle.

FIG. 3 shows a state in which the particle (P) accepts gravity (Fw) and electrostatic force (Fe), where F indicates a resultant force, q indicates an amount of electric charge, and E indicates an electrostatic field. , M indicate the mass of the particle, g indicates the gravitational constant, V indicates the voltage, and d indicates the gap between the bottom of the reticle and the top of the base. Thus, factors for adsorbing the particles (P) on the base to the bottom of the reticle include particle size (weight), the amount of charge on the reticle, and the distance between the bottom of the reticle and the top surface of the base.

Therefore, an object of the present invention is a reticle pod having antistatic performance, in which the reticle pod has a base having a supporting surface, the supporting surface has a recess formed by a bottom surface, and the reticle pod is a base. It further has a plurality of support members configured to support the reticle while surrounding the support surface of the reticle, the recess is defined by the depth extending between the support surface and the bottom surface, and the depth adheres to the support surface. It is an object of the present invention to provide a reticle pod characterized by being in the range of 300 μm to 3400 μm so as to weaken the electrostatic force exerted on the particles.

In certain embodiments, the base further has an upward facing contact surface that is in contact with the lid to form an airtightly sealed receiving space surrounding the carrier surface.

In certain embodiments, the recess has a ring-shaped edge that surrounds a zone with an area equal to or greater than the area of the pattern zone of the reticle.

In certain embodiments, the recess has a ring-shaped edge that surrounds the zone sufficient to cover the pattern zone of the reticle.

In certain embodiments, the recess has a rectangular edge that is 138 mm long and 110 mm wide.

In certain embodiments, the residual voltage of the reticle is greater than 50 V and the depth is greater than at least 400 μm.

Another object of the present invention is a reticle pod with antistatic performance, where the reticle pod has a base with an upper surface, the upper surface is a deflection surface formed by mechanical processing, and the reticle pod is the upper surface. It further has a plurality of support members configured to support the reticle while surrounding the reticle, and static electricity exerted on the particles adhering to the upper surface of the base between the downwardly facing surface of the reticle and the upper surface of the base. It is an object of the present invention to provide a reticle pod characterized in that a gap of at least 300 μm is formed so as to weaken the force.

In certain embodiments, the base further has an upward facing contact surface that surrounds the top surface and is in contact with the lid to form an airtightly sealed receiving space.

In certain embodiments, the area of the top surface is equal to or greater than the area of the pattern zone of the reticle.

In certain embodiments, the top surface zone is sufficient to cover the pattern zone of the reticle.

In certain embodiments, the top surface has a rectangular edge that is 138 mm long and 110 mm wide.

In certain embodiments, the residual voltage of the reticle exceeds 50 V and the clearance exceeds at least 400 μm.

Yet another object of the present invention is a method for processing a reticle pod used for a base of a reticle pod, in which the base has a support surface and a plurality of support members, and the plurality of support members surround the support surface of the base. The purpose is to provide a method of making it a constituent requirement that the reticle is configured to support the reticle in a state of being. The method comprises the step of mechanically processing the carrier surface to form a recess on the carrier surface, the recess being composed of a bottom surface, the method of processing the recess and making the recess according to the residual voltage of the reticle. Further including steps defined by depth, the depth exceeds at least 300 μm.

In certain embodiments, the residual voltage is greater than 50 V and the depth is greater than at least 400 μm.

In certain embodiments, the residual voltage is greater than 100 V and the depth is greater than at least 400 μm.

In certain embodiments, the residual voltage is greater than 200 V and the depth is greater than at least 800 μm.

In certain embodiments, the residual voltage is greater than 400 V and the depth is greater than at least 1600 μm.

The contents of this disclosure are shown in the accompanying drawings, which will be described below. Non-limiting and non-exhaustive embodiments are provided below with respect to the accompanying drawings. The accompanying drawings are intended to explain the technical features and principles, but are not necessarily drawn to scale.

It is an exploded view (prior art) of the conventional reticle pod. It is a figure (prior art) which shows the step of approaching a charged particle to the base of a reticle pod. It is a figure (prior art) which shows the particle under electrostatic force and gravity. It is an exploded view of the reticle pod of this invention. It is a perspective view of the base of a reticle pod. It is sectional drawing based on FIG. FIG. 5 is a plan view of the base of the reticle pod of FIG. It is a bottom view of the base of the reticle pod of FIG. It is a figure which shows the relationship between the reticle pattern zone and the concave cover zone. It is a figure which shows the gap between a reticle and the bottom surface of a recess. It is a perspective view of the base of the reticle pod which concerns on another embodiment of this invention. It is a figure which shows the influence of the residual voltage, the particle size and the gap of a reticle on the net force exerted on a particle. It is a figure which shows the influence of a different residual voltage, a different particle size and a different gap of a reticle on a net force exerted on a particle. It is a figure which shows the influence of a different residual voltage, a different particle size and a different gap of a reticle on a net force exerted on a particle. It is a figure which shows the influence of a different residual voltage, a different particle size and a different gap of a reticle on a net force exerted on a particle.

The present disclosure is described below with reference to the accompanying drawings and is exemplified by specific embodiments. However, the content claimed by the present disclosure can embody the content claimed in different forms from each other, and thus the scope is not limited to the exemplary examples and embodiments disclosed below. Illustrated examples and embodiments serve only explanatory purposes. The content of this disclosure provides a reasonably wide range of content claimed.

The expression "in one embodiment" as used herein does not necessarily refer to the same embodiment. The phrase "in another embodiment" as used herein does not necessarily refer to specific embodiments that differ from each other. The claimed content, in whole or in part, should be considered to belong to the scope of the combination of exemplary embodiments and embodiments.

FIG. 4 is an exploded view of the reticle pod of the present invention. Similar to FIG. 1, FIG. 4 shows an outer pod (200) and an inner pod (210). The outer pod (200) has a lid (201) and a base (202). The lid (201) and base (202) together define a receiving space for receiving the inner pod (210). The inner pod (210) further has a lid (211) and a base (212), the lid (211) and the base (212) together defining a receiving space for receiving the reticle (220). The technical feature of the present invention in the present disclosure is in the base (212). Other details of the outer pod (200) and the inner pod (210) lid (211) are omitted in the following description.

The base (212) has a plurality of support members (2121), an upwardly facing support surface (hereinafter referred to as a support surface (2122)) and an upwardly facing contact surface (2123). The support member (2121) is provided between the support surface (2122) and the upward facing (2123) and surrounds the support surface (2122). The support members (2121) are configured to take different shapes to support the bottom or side edges of the reticle (220). For example, in this embodiment, each support member (2121) is in contact with two limiting posts for limiting lateral displacement of the reticle (220) and a downward facing surface of the reticle, thus the reticle (220). It has a support pin that lifts above the carrier surface (2122). The gap between the downward facing surface of the reticle (220) and the supporting surface (2122) is determined by the height of the support pin. Basically, the carrier surface (2122) is flat, but in practice at least a portion of the carrier surface (2122) is a surface that is machined but rarely discernible to the naked eye. The carrier surface (2122) is mechanically machined to form a recess (2124) in it. The recess (2124) is not only substantially centered at the carrier surface (2122), but is surrounded by the carrier surface (2122). When the reticle (220) is located on the support member (2121), the pattern zone of the reticle (220) coincides with the recess (2124).

FIG. 5 shows the fine structural features of the base (212). FIG. 6 is a cross-sectional view taken along the broken line of FIG. As shown, a groove (not shown by reference numeral) is formed around the base (212) between the carrier surface (2122) and the upwardly facing contact surface (2123). The grooves are adapted to capture particles that have entered the junction between the lid (211) and the base (212). FIG. 6 shows that the carrier surface (2122) is higher than the upward contact surface (2123), thereby forming a structural barrier, thus reducing the risk of particles falling onto the carrier surface (2122). Clearly guarantees the cleanliness of the inner pod (210). In the modified embodiment, the carrier surface (2122) and the upward contact surface (2123) are flush with each other, or the carrier surface (2122) is lower and the groove is also completely. Good to be satisfied. The recess (2124) is defined by a bottom surface (600) and a wall surface (601) and thus is defined by a depth (D). The depth (D) is the machining depth, that is, the vertical distance between the carrier surface (2122) and the bottom surface of the recess (600), as shown in FIG. Since the recesses (2124) are also formed by mechanical machining, the bottom surface (600) may also be deflected.

FIG. 7 is a plan view of the base (212) of FIG. As shown, the opening (defined by the inner edge of the supporting surface) and bottom surface (600) of the recess (2124) are rectangular, and both the opening and the bottom surface (600) are substantially. Have the same area. In one embodiment, the rectangles are 138 mm long and 110 mm wide, respectively. The recess (2124) is substantially centered at the carrier surface (2122), and the recess is not in contact with any side of the carrier surface. FIG. 8 is a bottom view of the base portion (212) of FIG. 5, in which the base portion (212) is positioned in the processing machine with the positioning structure (800) provided at the bottom portion of the base portion (212). It shows that there is.

FIG. 9A is a plan view showing the relationship between the reticle pattern region (901, bounded by the surrounding solid line) and the base recessed region (902) of the reticle (900). The dashed line in the figure indicates the ring-shaped edge of the recess opening, which indicates that the recess cover area (902) is at least wider than the reticle pattern area (901). With this configuration, every part of the reticle pattern zone faces the bottom of the recess. FIG. 9B is a side view showing a gap (G) provided between the downwardly facing surface of the reticle pattern region (901) and the bottom surface (903) of the recess. Depending on the height of the reticle to be supported, the height of the bottom surface of the reticle (904) should be approximately equal to the height of the supporting surface of the base, the bottom surface of the reticle (904) and the bottom surface of the recess (600). The gap between the and the recess is equal to the depth of the recess (depth D shown in FIG. 6). In one embodiment, the recess depth (D) ranges from 300 μm to 3400 μm, or from 3400 μm to 3750 μm. Thus, the gap (G) is at least greater than 300 μm. Therefore, when a statically charged reticle is placed on the base, it effectively weakens the electrostatic force exerted on the particles on the supporting surface of the base by adjusting the recess depth (D) or gap (G). It can thus reduce the risk of particles being attracted to the downward facing surface of the reticle.

FIG. 10 is a perspective view of the base of the reticle pod according to another embodiment of the present invention. Compared to FIG. 5, FIG. 10 shows a significant reduction in the zones of the carrier surface within the base and an increase in the recessed cover zones forming the top surface (1002) surrounded by the continuous wall (1001) as well as the wall (1001). ) Is slightly higher than the upwardly facing contact surface (1003), thereby reducing the risk of contaminated particles entering the top surface (1002). In the modified embodiment, the wall (1001) is not required and the illustrated groove separates the upwardly facing contact surface from the top surface. Similarly, the electrostatic force exerted on the particles on the top surface of the base is effective in forming a gap between the reticle on the base and the downward facing top surface (1002) and in properly adjusting the depth of the top surface (1002). The vertical height of the wall (1001) can be, for example, in the range of 300 μm to 3400 μm, or the gap between the bottom and top surfaces of the reticle (1002) is at least. It can be larger than 300 μm.

11A-11D are diagrams showing the effects of different residual voltages of the reticle, different particle sizes and different gaps on the net force exerted on the particles. FIG. 11A shows six particles of different particle sizes according to the morphology shown in FIGS. 6 and 9, especially when the particles are located on the bottom surface (903) of the recess and the residual voltage of the reticle is 400V. It is a graph showing the relationship between the net force and the depth (D), and as shown by the graph, when the depth is larger than 1600 μm, the net force of all the particles becomes negative, and this This suggests that the particles receive a downward force, which effectively weakens the electrostatic force exerted on the particles. Similarly, FIG. 11B is a graph showing the relationship between the net force exerted on the particles having the above particle size and the depth (D) when the residual voltage of the reticle is 200 V, and is shown by the graph. As such, when the depth is larger than 800 μm, the electrostatic force exerted on the particles is effectively weakened. FIG. 11C is a graph showing the relationship between the net force exerted on the particles having the above-mentioned particle size and the depth (D) when the residual voltage of the reticle is 100 V, as shown by the graph. In addition, when the depth is larger than 400 μm, the electrostatic force exerted on the particles is effectively weakened. FIG. 11D is a graph showing the relationship between the net force exerted on the particles having the above-mentioned particle size and the depth (D) when the residual voltage of the reticle is 50 V, and is shown by these graphs. As such, when the depth exceeds 400 μm, the electrostatic force exerted on the particles is effectively weakened. In the above figure, the graphs are not color coded in such a way that they are distinguished from each other according to the particle size, but those skilled in the art will identify the graphs from each other according to the disclosure contents shown in the figure, thereby the above-mentioned figure. It will still be possible to understand the explanation of.

Therefore, the present disclosure provides a reticle pod. The residual voltage of the reticle to the particles on the surface of the base by adjusting the machining depth of the recess provided at the base of the reticle pod or the gap between the bottom surface (top) of the recess and the downward facing surface of the reticle. The effect of the reticle is effectively diminished, thus reducing the risk of particles being attracted to the downward facing surface of the reticle, thereby protecting the pattern zone from contamination.

100 Outer pods 101,111 Lid 102,112 Base 110 Inner pod 120 Reticle 212 Base 600 Bottom 601 Wall surface 1121 Support member 1122 Support surface 1123 Upward contact surface 2121 Support member 2122 Upward contact surface 2124 Recess D depth G gap

Claims (17)

A reticle pod with antistatic performance
It has a base with a supporting surface, the supporting surface having a recess configured by a bottom surface.
It has a plurality of support members configured to support the reticle while surrounding the support surface of the base.
The recess is defined by a depth extending between the supported surface and the bottom surface, the depth in the range of 300 μm to 3400 μm to weaken the electrostatic force exerted on the particles adhering to the supported surface. There is a reticle pod. The reticle according to claim 1, wherein the base further has an upwardly facing contact surface that is in contact with the lid so as to form an airtightly sealed receiving space surrounding the supporting surface. Pod. The reticle pod according to claim 1, wherein the recess has a ring-shaped edge surrounding a zone having an area equal to or larger than the area of the pattern zone of the reticle. The reticle pod according to claim 1, wherein the recess has a ring-shaped edge surrounding a zone sufficient to cover the pattern zone of the reticle. The reticle pod according to claim 1, wherein the recess has a rectangular edge having a length of 138 mm and a width of 110 mm. The reticle pod according to claim 1, wherein the residual voltage of the reticle exceeds 50 V, and the depth exceeds at least 400 μm. A reticle pod with antistatic performance
It has a base with an upper surface, the upper surface being a deflection surface formed by mechanical processing.
It has a plurality of support members configured to support the reticle while surrounding the upper surface, and adheres to the upper surface of the base between the downwardly facing surface of the reticle and the upper surface of the base. A reticle pod with a gap of at least 300 μm formed to weaken the electrostatic force exerted on the particles. 17. The reticle pod of claim 7, wherein the base further comprises an upward facing contact surface that surrounds the top surface and is in contact with the lid to form an airtightly sealed receiving space. The reticle pod according to claim 7, wherein the area of the upper surface is equal to or larger than the area of the pattern zone of the reticle. The reticle pod according to claim 7, wherein the upper surface zone is sufficient to cover the pattern zone of the reticle. The reticle pod according to claim 7, wherein the upper surface has a rectangular edge having a length of 138 mm and a width of 110 mm. The reticle pod according to claim 7, wherein the residual voltage of the reticle exceeds 50 V, and the gap exceeds at least 400 μm. A method for processing a reticle pod used for a base of a reticle pod, wherein the base has a supporting surface and a plurality of supporting members, and the plurality of supporting members surround the supporting surface of the base. The method is configured to support the reticle.
A step of mechanically processing the supported surface to form a recess on the supported surface, wherein the recess is composed of a bottom surface.
A method comprising processing the recess and defining the recess by a depth corresponding to the residual voltage of the reticle, wherein the depth exceeds at least 300 μm. 13. The method of claim 13, wherein the residual voltage exceeds 50 V and the depth exceeds at least 400 μm. 13. The method of claim 13, wherein the residual voltage exceeds 100 V and the depth exceeds at least 400 μm. 13. The method of claim 13, wherein the residual voltage exceeds 200 V and the depth exceeds at least 800 μm. 13. The method of claim 13, wherein the residual voltage exceeds 400 V and the depth exceeds at least 1600 μm.

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